a measure of the degree to which the total phenotype variance is the result of genetic differences and thus can be influenced by selection
Source: Jenkins, John B. 1990. Human Genetics, 2nd Edition. New York: Harper & Row ...
Heritability of methylation Î"age. (A) Intra-class correlation of Hannum and Horvath Î"age across relationship class. (B) Heritability of Hannum and Horvath Î"age in BSGS data. Both plots show estimates with standard errors. *Pseudo-independent pairs.
Heritability: The proportion of the total phenotypic variance that is attributable to hereditary variance (h2= genetic variance / total phenotypic variance). A high h2 does not mean that the trait cannot be influenced by environment. In a different environment, h2 may not be that high.
While some behaviors are indeed attributable to a single gene, most behavioral traits are polygenic, or influenced by several genes. Further, more often than not, the environment will mediate the affects of those genes.
Aggression, as well as other behavioral traits, is studied genetically based on its heritability through generations. Heritability models of aggression are mainly based on animals due to the ethical concern in using humans for genetic study.
H#178;. The proportion of total phenotypic variance at the population level that is contributed by genetic variance (also called ~ in the broad sense).
- A measure of resemblance between relatives. In the broad sense,
~ (in the narrow sense)A measure of the extent to which genes inherited from parents determine phenotypes; defined as the ratio of the additive genetic variance to total phenotypic variance; also called realized ~.
genetic factors — tall parents tend to have tall children
or — most likely — both.
The infectivity and ~ of yeast prions and the ease of yeast manipulation as exemplified by the work of Vishveshwara and Liebman  make possible detailed studies of different amyloid forms, their generation and interaction with each other and with other cellular components, ...
In Darwin's time, there was no widely accepted in-depth mechanism for ~. However, it is now known that most inherited variation can be traced to discrete, persistent entities called "genes", which are aspects of a linear molecule called DNA.
Genomic imprinting (which is "epigenetic") constitutes ~ that is not coded in DNA. Evolution is prevalent also in viruses, although these are not considered to be organisms. The genetic material in viruses may consist of DNA or RNA.
Principles of molecular evolution
Numerous scientists during Mendel's time were studying the ~ of various traits. However, much of this science was descriptive and qualitative.
Types of mutation explained (chromosomal and gene) OR given in terms of ~ i.e. germ cf. somatic cell mutation;
Cause of mutation (high energy radiation/ particles OR named chemical mutagen); ...
~ — The proportion of phenotypic variation that is explained by genetic factors.
Heteroplasmy — The occurrence in a single cell of more than one population of mitochondrial DNA sequence.
See also: What is the meaning of Organ, Genetics, Trait, Population, Environment?